Buspirone is a serotonin (5-HT(1A)) agonist which stimulates the secre- tion of cortisol, prolactin & growth hormone in normal volunteers. The concentration of serotonin in the CNS may be abnormally low in various psychiatric disorders. Administration of buspirone to psychiatric pts & the subsequent measurement of their hormone responses may reflect abnor- al serotonergic function in these pts as compared to normal volunteers.